Power supply systems are pervasive in many electronic applications from computers to automobiles. Generally, voltages within a power supply system are produced by performing a DC/DC, a DC/AC, and/or an AC/DC conversion by operating a switch loaded with an inductor or transformer. DC-DC converters, such as buck converters, are used in systems that use multiple power supplies. For example, in an automotive system, a microcontroller that nominally operates at a 5V power supply voltage may use a switched-mode power supply, such as a buck converter to produce a local 5V power supply from the 12V car battery. Such a power supply may be operated by driving an inductor using a high-side switching transistor coupled to a DC power supply. Under moderate to heavy load conditions, the output voltage of the power supply is controlled by varying the pulse-width of the time during which the switching transistor is in a conductive state.
Under lightly loaded conditions, however, using a normal regulation scheme using a pulse width modulated drive signal may pose difficulties with respect to stability and converter efficiency. As such, some conventional power converters operate using a burst mode control scheme in which the switching transistor is pulsed on and off for a short burst period followed by a long period in which no switching occurs. In some cases, however, the output voltage of such switched-mode power supply systems may be prone to transients as the power supply transitions in and out of the burst mode.